US Patent 7774915 Ductile iron pressure fit gasket

A sealing gasket is shown for use in a ductile iron piping system to form a sealed joint between mating male and female pipe ends. A sealing gasket body is provided with a series of retainer inserts which extend outwardly from a leading nose region of the elastomeric gasket body. The mating male pipe end contacts the retainer inserts prior to contacting the remainder of the gasket body during the make up of the pipe joint. The inserts help to retain the gasket within its associated groove during high pressure field conditions. The inserts are spaced circumferentially about the gasket nose region, allowing the gasket the necessary flexibility to allow insertion within the groove provided in the female, belled pipe end.